I've had sight of a study whose results show that violin and piano (and by extension, keyboards in general) have learning curves of similar character once you get past the first few days. For me this is both encouraging and awe-inspiring: I know where I'll be with my keyboard in seven months' time.
I had my first serious fumble between C3 and C5 this evening, and I was surprised by how my left hand was less responsive than my right, specifically my middle and ring left-hand fingers. These are the most mobile when playing strings, while the right-hand fingers keep station on the frog end of the bow. Perhaps keyboard playing may help my fingering agility on the fiddle, if not my intonation.
For the foreseeable future there is little scope for personal tuition. I am very self-propelled (an OU graduate) and almost entirely self-taught on the violin. Has anyone any advice on the better etudes and exercises for an old, stoic, introvert wannabe keyboardist?